When can you use connector blocks

[broadway]

I am thinking about replacing our 6 kitchen spotlights with Halogens as I am fed up with replacing them. After looking at the wiring I am not sure that I like the way it is has done.

The junction box feeding the lights has a a feed from the live and switch using twin and earth cable. From the junction box there are 3 PVC feeds coming out, on each cable is a connection block acting as a junction connecting to a light and another PVC cable that terminates with a connector block to a lamp.

Is it acceptable to use connectors in this fashion and should you have more than 4 cables on a junction box?

 

[breezer]

I am thinking about replacing our 6 kitchen spotlights with Halogens as I am fed up with replacing them.

what lights have you now? halogen lamps have a "short life" (depending on brand etc), could you not fit "low energy lamps"?

 

[broadway]

The current lights are RO 80 screw. The light fittings need replacing as some positions seem to blow immediately and on the others are reluctant to accept the bulbs.

We have some low-energy lamp, but my wife does not like the light quality of them and she likes the halogens in a friends house.

 

[Big_Spark]

The current lights are RO 80 screw. The light fittings need replacing as some positions seem to blow immediately and on the others are reluctant to accept the bulbs.

We have some low-energy lamp, but my wife does not like the light quality of them and she likes the halogens in a friends house.

Keep the Halospots, but change what you have and tidy the whole mess up. RO80 spots should last about twice as long as dichroic halogens, some even longer.

I would suggest that you buy a decent track and get some 230V halogen spots for it. Ensure that you have a good clean feed and make sure all connections are tight.

One thing to consider is changing the light switch in the kitchen. Old worn switches tend to generate spikes on the supply as they are switched, halogens are prone to these and it does effect their life span.

Get a good quality switch, MK or Crabtree, that will help.

For tracks etc, try
here

 

[kendor]

FWL wrote: One thing to consider is changing the light switch in the kitchen. Old worn switches tend to generate spikes on the supply as they are switched

I would question the word "spikes" in your reply i would have said that old worn out switches are prone to arcing due to pitting, dirt, it's the actual load that generates the spikes, ie inductive loads such as motors, flourescents etc. this is where the double current capacity of the load switch rating comes into play.

 

[Big_Spark]

I would question the word "spikes" in your reply i would have said that old worn out switches are prone to arcing due to pitting, dirt, it's the actual load that generates the spikes, ie inductive loads such as motors, flourescents etc. this is where the double current capacity of the load switch rating comes into play.

Ken, I think your being over picky, we are not dealing with someone with a high degree of electrical knowledge so a simple description will suffice, however to be picky, the arc of a light switch will cause a momentary spike in the supply along the cable in question. Inductive loads do cause spikes, you are correct, however the majority, but not all, will occur on the neutral as a harmonic.

The majority of phase line spikes on inductive loads if often the result of the inrush current on start up, although any switch in the system will induce momentary spikes, whether that switch be a normal switch, contactor or orther such device.

The only way around this problem, is what you mentioned in a post about a lighting problem, and that is soft start. Howver this is not practical for every situation....more is the pity.

 

[kendor]

I was directing my comment towards you rather than the author.
I think this is going to boil down to what each of us defines as a spike,
To me a spike is a momentary overvoltage on the supply, I have to disagree regarding an arcing switch "inducing" a spike on the mains If anything a certain amount of Rectification would be taking effect as in the old Mercury filled Arc type Rectifiers.
regarding an inductive load, the moment a switch was broken feeding such a load then a spike would be induced on the mains, One ( this is bolded for breezers benefit so he doesn't start having a go because i didn't mention all the reasons)of the reasons why flourescent lights in a large office block are switched on/off in stages using BMS or PLC's to stop large inductive loads being switched off causing large spikes.
Going back to the original post the authors circuit comprises of R80 reflector lamps this circuit would be almost resistive as opposed to inductive and therefore breaking of the worn switch whilst it may produce arcing, would NOT produce Spikes of any consequence , of course switching off a heavy resistive load would produce a spike on the mains but not the 6 R80's quoted.

 

[Big_Spark]

Ken, I was fully aware in which direction your comment was aimed, and I will disagree with your definition of spike.

A spike in any electrical system is a voltage which occurs, momentarilly, outside the fundermental parameters of that system.

The spike can actually be at the same voltage, however if the frequency is different a spike will result.

Arcing in any switching mechanism of any electrical system is capable of producing a spike unless measure have been taken to prevent such spikes from propagating, however domestic installations are not built to that standard.

Regarding the rectification, the arc will have very minimal effect in this area, however even here a dc voltage induced on the line by the arc is still a spike, and these can effect the operation of certain electrical equipment.

Tungsten filament and Tungsten Halogen lamps are susceptible to all spikes, whether ac or dc, some more so than others. Discharge lighting is less effected due to the control tending to being the biggest culprit of interference in the system..as you rightly pointed out.

 

[securespark]

Ding Ding!! Round Two!!

 

[AdamW]

You know, this is the problem with having electrical engineers. In the old days you had plain old electricians who could make circuits just work without any of this disagreement. Now we end up with a diatribe over spikes on a lighting circuit

Reminds me of the episode of "Dexter's Lab" where the electrician fixed up the nuclear reactor to work at 100% efficiency.

As a common-or-garden physicist in a "heightened state of refreshment" (i.e. a bottle of a rather nice red inside me ) I will ask you to humour me on this one, but surely a "spike" is any delta function, whether it be in the energy or time domain?

However, reading all the posts I think you are both getting at the same thing. In the case of an old/dirty/pitted switch, or indeed any switch in the real world, this will present a load to the supply. Thus if you apply one of those lovely theorems that electrical/electronic types love, such as Kirchhoff or superposition, then it all adds up to zero and energy is conserved. Which makes me, as a physicist, ecstatic.

 

[broadway]

I don't think it is the switch as some positions blow more often than others. At the moment we only use the 3 "best" ones. The other 3 are empty as they blow too frequently.

I thought I had read somewhere that halogens had a longer life than ro80 bulbs, but I may have misread something..

 

[Big_Spark]

Broadway, it will all depend on manufacturer, and whether anyone is giving that advice whilst peddling halogen lights and lamps

 

[ban-all-sheds]

I've got RO80s. One's a 60W, and it lasts forever, but it's another story with the 100s. The ones on dimmers aren't too bad, but the undimmed ones have a distressingly short life.

As they were undimmed I did try some low-energy equivalents, and was getting on splendidly with the GE Genura lamps, until one exploded one day, spraying out shards of glass and molten metal. Nobody underneath, fortunately, but I didn't want to take any more risks so back went the incandescents...

I would never recommend them to anybody.

BTW, broadway - don't forget that whenever you see a bulb life quoted, chances are it refers to the time by which 50% of the bulbs fail.....

 

[kendor]

The spike can actually be at the same voltage, however if the frequency is different a spike will result.

Myself and several engineers at work had a chuckle over your reply( it took us a while to fathom your use of english and reasoning in the above sentence) , If the "spike"(the name says it all) was at the same voltage as the sine wave at that particular moment in time then you wouldn't see it! (common sense) To elaborate on my previous post a Spike is an overvoltage peak on a sine wave(or other wave) at an instance in time .
I havnt even got the energy left (or the will to live )anymore to have to answer back regarding your comments about "Harmonics" in this subject, again it generated a lot of amusement in it's irrelevance.

 

[Big_Spark]

Ken, I really think you should go back to college and do some serious education, you obviously know nothing about what your trying to talk about if you feel you know more than the entire Engineering and Scientific communities of the entire planet.